McIDAS images of GOES-13 0.63 Âµm visible channel data during the day and 3.9 Âµm shortwave IR data at night (above; click image to play animation) revealed a number of very large and dense smoke plumes from wildfires that were burning in parts of the northwestern US (primarily in Idaho) on 28 August – 29 August 2012. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as very 5-10 minutes.

During the following overnight hours, AWIPS images of Suomi NPP VIIRS 0.8 Âµm Day/Night Band (DNB), 3.74 Âµm shortwave IR, and 11.45 Âµm IR data (below) demonstrated the value of the DNB providing a visible channel at night (under ideal conditions of illumination by ample moonlight). While the 11.45 Âµm IR image verified that there were some patches of meteorological cloud in the region, the majority of the bright features seen on the DNB image were thick airborne smoke.

A night-time image comparison of the VIIRS 0.8 Âµm Day/Night Band and the corresponding 3.74 Âµm shortwave IR (below) revealed areas of smoke that were trapped in some of the valleys of central Idaho at 09:34 UTC (3:34 AM local time) on 31 August 2012.

Isaac reached Category 1 hurricane intensity mid-day on 28 August 2012. AWIPS images of 1-km resolution visible and IR data from the VIIRS, AVHRR, and MODIS instruments (below) showed curved banding features and convective bursts with overshooting tops, along with cloud top IR brightness temperatures as cold as -86Âº C.

Suomi NPP VIIRS 0.64 Âµm visible and 11.45 Âµm IR images at 18:33 UTC

POES AVHRR 0.86 Âµm visible and 12.0 Âµm IR images at 19:25 UTC

MODIS 0.65 Âµm visible and 11.0 Âµm IR images at 19:41 UTC

McIDAS images of 1-minute interval Super Rapid Scan Operations for GOES-R (SRSOR) 0.63 Âµm visible channel and 10.7 Âµm IR channel data (below) showed the detail and temporal evolution of the convective bursts that developed near the center of the circulation of Hurricane Isaac as it made landfall over the Mississippi River delta region along the southeast Louisiana coast around 23:45 UTC.

GOES-14 0.63 Âµm visible images (click image to play animation)

GOES-14 10.7 Âµm IR images (click image to play animation)

===== 29 August Update =====

A comparison of night-time AWIPS images of Suomi NPP VIIRS 0.8 Âµm Day/Night Band data with the corresponding 11.45 Âµm IR data (below) at 08:29 UTC (3:29 AM local time) showed some spiral banding structure within the eastern semicircle of Isaac, along with an isolated area of deep convection immediately offshore (the minimum IR brightness temperature associated with this feature was -88 C). City lights could be seen in the northwestern portion of the image, where there were breaks in the clouds or only a thin veil of high clouds covered the area.

When two tropical cyclones are within close proximity to each other, they will typically start a rotation around a common center. This interaction, called the Fujiwhara Effect, may be occurring in the image loop above. Typhoon Bolaven approaches Typhoon Tembin, and the distance between the two reaches a minimum on 23 August, after which time Tembin moves west and Bolaven moves northwest. Subsequent to Bolaven’s recurvature over the Korean peninsula, Tembin moves northward into midlatitudes as well.

The Day-Night Band on VIIRS, flying on the Suomi/NPP satellite gave an excellent view of Isaac at strong tropical storm strength in the northern Gulf of Mexico shortly after midnight on August 28 2012. VIIRS is providing something unique to forecasters: Visible imagery at night that allows easy identification of overshooting tops and cirrus blow-off, and cumulus fields in the Gulf of Mexico. The infrared window channel on VIIRS showed coldest cloud-top temperatures of -84 C, and also the effects of dry air on the tropical system. Convection is suppressed in the northern half of the storm. A zoomed-in annotated version of the above VIIRS image comparison is available here.

During the first few hours after sunrise, GOES-14 Super Rapid Scan Operations for GOES-R (SRSOR) visible imagery at 1-minute intervals (above; click image to play animation) showed the development of a number ofÂ convective elements around the center of Isaac’s circulation. After about 14 UTC, the rotation of the low-level circulation of Isaac could be seen as a “clear slot” opened up between areas of convection.